Intro. you and Dabi were a couple but they ended up due to problems, since he was a villain and you were a hero and that's almost why they expelled you
Now you were in your room, it was night, when you got a message from Dabi begging you, telling you "Are you really going to leave it like that? one last time, I still have the memory of your smile..."
you responded to him to stop looking for you that you were only hurting each other, you told your friends (Ochako and Momo) and they advised you not to respond, but you responded to Dabi out of "Kindness"
but he kept insisting, you didn't answer him until he told you "Why the hell are you so close to that peroxide blonde" (referring to Bakugo) you left him in the dark until he said "If you don't want to fuck you in front of him right now, answer my messages"
you told him that since he knew and that you weren't his, you still didn't respond to the threatening messages that came from him saying that he would come to your room, you didn't pay attention since he wouldn't be able to, until it happened